scholarly journals Effects of heterogeneity in infection-exposure history and immunity on the dynamics of a protozoan parasite

2007 ◽  
Vol 4 (16) ◽  
pp. 841-849 ◽  
Author(s):  
Maite Severins ◽  
Don Klinkenberg ◽  
Hans Heesterbeek
Keyword(s):  
Dynamic Behaviour ◽  
Protozoan Parasite ◽  
Host Population ◽  
Infection Process ◽  
Control Measures ◽  
Complex Dynamic ◽  
Systems Models ◽  
Exposure History ◽  
The Relationship ◽  
Initial Contamination

Infection systems where traits of the host, such as acquired immunity, interact with the infection process can show complex dynamic behaviour with counter-intuitive results. In this study, we consider the traits ‘immune status’ and ‘exposure history’, and our aim is to assess the influence of acquired individual heterogeneity in these traits. We have built an individual-based model of Eimeria acervulina infections, a protozoan parasite with an environmental stage that causes coccidiosis in chickens. With the model, we simulate outbreaks of the disease under varying initial contaminations. Heterogeneity in the traits arises stochastically through differences in the dose and frequency of parasites that individuals pick up from the environment. We find that the relationship between the initial contamination and the severity of an outbreak has a non-monotonous ‘wave-like’ pattern. This pattern can be explained by an increased heterogeneity in the host population caused by the infection process at the most severe outbreaks. We conclude that when dealing with these types of infection systems, models that are used to develop or evaluate control measures cannot neglect acquired heterogeneity in the host population traits that interact with the infection process.

scholarly journals Reduction in mobility and COVID-19 transmission

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Pierre Nouvellet ◽  
Sangeeta Bhatia ◽  
Anne Cori ◽  
Kylie E. C. Ainslie ◽  
Marc Baguelin ◽  
...  
Keyword(s):  
Predictive Ability ◽  
Control Measures ◽  
Social Distancing ◽  
Beneficial Effects ◽  
Mobility Data ◽  
Strict Control ◽  
Before And After ◽  
Proxy Measure ◽  
Lower Transmission ◽  
The Relationship

AbstractIn response to the COVID-19 pandemic, countries have sought to control SARS-CoV-2 transmission by restricting population movement through social distancing interventions, thus reducing the number of contacts. Mobility data represent an important proxy measure of social distancing, and here, we characterise the relationship between transmission and mobility for 52 countries around the world. Transmission significantly decreased with the initial reduction in mobility in 73% of the countries analysed, but we found evidence of decoupling of transmission and mobility following the relaxation of strict control measures for 80% of countries. For the majority of countries, mobility explained a substantial proportion of the variation in transmissibility (median adjusted R-squared: 48%, interquartile range - IQR - across countries [27–77%]). Where a change in the relationship occurred, predictive ability decreased after the relaxation; from a median adjusted R-squared of 74% (IQR across countries [49–91%]) pre-relaxation, to a median adjusted R-squared of 30% (IQR across countries [12–48%]) post-relaxation. In countries with a clear relationship between mobility and transmission both before and after strict control measures were relaxed, mobility was associated with lower transmission rates after control measures were relaxed indicating that the beneficial effects of ongoing social distancing behaviours were substantial.

scholarly journals Emerging trends of nosocomial Citrobacter species surgical wound infection: concern for infection control

1970 ◽  
Vol 9 (1) ◽  
pp. 10-14
Author(s):  
B Thapa ◽  
D Karn ◽  
K Mahat
Keyword(s):  
Infection Control ◽  
Wound Infection ◽  
Infection Process ◽  
Surgical Wound Infection ◽  
Control Measures ◽  
Drug Resistant ◽  
Surgical Wound ◽  
Disk Diffusion Test ◽  
Antibiotic Susceptibility Test ◽  
Study Results

Background Surgical wound infection is a common problem among patients who undergo operation. Several factors play important role in this infection process including endemic nosocomial infection without proper infection control measures. Objectives To study the occurrence of the pathogens in post-operative wound infections, their antibiotic resistance patterns, and comparison with published reports. Methods Various specimens obtained from the surgical wound during a period of four months were processed for bacteriological culture in the Department of Microbiology, Kathmandu Medical College, Kathmandu. Antibiotic susceptibility test was performed by Kirby-Bauer disk diffusion test for pathogens isolated. The relevant literatures were searched and compared with the present study. Results Among 79 culture positive cultures, Citrobacter sp. (n=23) was most frequently isolated from surgical wound infection. Twenty strains were multidrug resistant. In comparison with other studies, this study highlights the emergence multi-drug resistant Citrobacter sp. as a leading cause of surgical wound infection. E. coli, Staphylococcus aureus, Acinetobacter sp., Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus sp., and Enterobacter sp. were also isolated from 19, 13, 10, 8, 2, 2, and 2 cultures, respectively. More than 50% of these pathogens were resistant to most of the β-lactam antibiotics tested and most of them were multi-drug resistant while these pathogens showed variable level of resistance to fluroquinolones and amino glycosides. Conclusion The frequent isolation of multi-drug resistant nosocomial strains of Citrobacter sp. in surgical wound infection is a remarkable trend. This pathogen and their resistant genes could be endemic to the institution and can cause difficult-to-treat infection if infection control committee is not revitalized and infection control strategies are not implemented. Key words Citrobacter sp.; Multi-drug resistant; surgical wound infection. DOI: http://dx.doi.org/10.3126/njdvl.v9i1.5762 NJDVL 2010; 9(1): 10-14

scholarly journals O paradigma científico no discurso da mídia brasileira sobre Zika e microcefalia

2018 ◽  
Vol 2 (1) ◽  
pp. 9
Author(s):  
Juliane Lopes Ferreira dos Santos ◽  
Denise Silva Matias ◽  
Nauana Nascimento Novais
Keyword(s):  
Control Measures ◽  
Scientific Paradigm ◽  
Scientific Debate ◽  
The Public ◽  
Emergency Situations ◽  
Biological Causation ◽  
The Media ◽  
The Subject ◽  
Official Sources ◽  
The Relationship

Introduction: In 2015 Brazil was surprised by an increase in the incidence of microcephaly, related by the Ministry of Health to Zika virus infection during pregnancy. This theme, which was notorious for public health, reached wide popular repercussion through the media. Objectives: To describe the presence of the scientific paradigm in the discourse of health professionals, researchers or journalists who inform the lay public about biological causation. Methodology: All the news made available on the digital platform of the Folha de São Paulo newspaper, containing the key term "Zika and microcephalia" and published between November 11, 2015 and March 4, 2016, was performed. Scientific elucidation on the subject. The news items were classified as to the presence of certainty or uncertainty about the relationship between Zika and microcephaly in their content and the central idea in the subject titles. Results: Of the 387 reports analyzed, 51.4% related Zika as a causal factor of microcephaly, while 32.8% considered the presence of uncertainty in the relationship. It was verified that the newspaper privileged subjects related to the repercussions due to the diseases, being predominant the report of control measures. Considering the origin of the news, it was significant the use of official sources, presented in 82% of the news. Conclusion: The scientific paradigm was disregarded, ignoring the uncertainty principle and the scientific debate. The limitations of both journalists and health managers were also demonstrated in the elaboration of an effective communication with the public in emergency situations.

scholarly journals Toward a Country-Based Prediction Model of COVID-19 Infections and Deaths Between Disease Apex and End: Evidence From Countries With Contained Numbers of COVID-19

2021 ◽  
Vol 8 ◽  
Author(s):  
Tianshu Gu ◽  
Lishi Wang ◽  
Ning Xie ◽  
Xia Meng ◽  
Zhijun Li ◽  
...  
Keyword(s):  
Real Data ◽  
Control Measures ◽  
Actual Number ◽  
The Public ◽  
The Us ◽  
Multiple Regression Models ◽  
Before And After ◽  
Using Data ◽  
High Degree ◽  
The Relationship

The complexity of COVID-19 and variations in control measures and containment efforts in different countries have caused difficulties in the prediction and modeling of the COVID-19 pandemic. We attempted to predict the scale of the latter half of the pandemic based on real data using the ratio between the early and latter halves from countries where the pandemic is largely over. We collected daily pandemic data from China, South Korea, and Switzerland and subtracted the ratio of pandemic days before and after the disease apex day of COVID-19. We obtained the ratio of pandemic data and created multiple regression models for the relationship between before and after the apex day. We then tested our models using data from the first wave of the disease from 14 countries in Europe and the US. We then tested the models using data from these countries from the entire pandemic up to March 30, 2021. Results indicate that the actual number of cases from these countries during the first wave mostly fall in the predicted ranges of liniar regression, excepting Spain and Russia. Similarly, the actual deaths in these countries mostly fall into the range of predicted data. Using the accumulated data up to the day of apex and total accumulated data up to March 30, 2021, the data of case numbers in these countries are falling into the range of predicted data, except for data from Brazil. The actual number of deaths in all the countries are at or below the predicted data. In conclusion, a linear regression model built with real data from countries or regions from early pandemics can predict pandemic scales of the countries where the pandemics occur late. Such a prediction with a high degree of accuracy provides valuable information for governments and the public.

scholarly journals Is the Prevalence of Leishmania infantum Linked to Breeds in Dogs? Characterization of Seropositive Dogs in Ibiza

Animals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2579
Author(s):  
Maria Edo ◽  
Pablo Jesús Marín-García ◽  
Lola Llobat
Keyword(s):  
Immune Response ◽  
Leishmania Infantum ◽  
Protozoan Parasite ◽  
Disease Stage ◽  
Doberman Pinscher ◽  
Th2 Immune Response ◽  
Mediterranean Island ◽  
Antibody Titers ◽  
The Relationship

Leishmaniosis is an important zoonotic protozoan disease primarily spread to the Mediterranean region by Leishmania infantum, the predominant protozoan species, which accounts for the majority of cases. Development of disease depends on the immune response of the definitive host and, predictably, their genetic background. Recent studies have revealed breed-typical haplotypes that are susceptible to the spread of the protozoan parasite. The objective of this study was to analyze the prevalence of leishmaniosis on a Mediterranean island and determine the relationship between disease prevalence and breed. In addition, information on seropositive animals was recorded to characterize animals affected by the disease. To study the prevalence, a total of 3141 dogs were analyzed. Of these, the 149 infected animals were examined for age, sex, antibody titer, and disease stage. We observed a prevalence of 4.74%, which varied between breeds (p < 0.05). The Doberman Pinscher and Boxer breeds had the highest prevalence of leishmaniosis. Significant differences were observed between breeds with common ancestors, emphasizing the important genetic component. Finally, regarding the characterization of seropositive animals, the distribution is similar to other studies. We discovered a relationship (p < 0.05) between the number of antibody titers and the clinical disease stage, which was also present in Leishmania infantum, suggesting that the development of the disease depends on the humoral or Th2 immune response with ineffective antibodies.

Study on the Relationship between Supervisors' Remuneration in Listed Companies and Tobacco Control Measures

2021 ◽  
Vol 7 (6) ◽  
pp. 5074-5086
Author(s):  
Miao Wang ◽  
Pengfei Li
Keyword(s):  
Theoretical Study ◽  
Company Law ◽  
Theory And Practice ◽  
Control Measures ◽  
Clear Understanding ◽  
Corporation Governance ◽  
Legal Principle ◽  
Self Consistent ◽  
The Difference ◽  
The Relationship

Objectives: At present, the theoretical study on supervisors' remuneration under the Company Law is still too principled, and many "chaos" occur in the remuneration practices for supervisors. First, the lack of clear understanding of the incentive function and institutional specificities of supervisors' remuneration results in many problems in the application of supervisors' remuneration in practice, as well as the ignoration of the Board of Supervisors in corporation governance. Second, rather than reaching the intended effect, the legislative approach of authorized "blank" intentionally adopted under the Company Law leaves an inducement for the ineffective supervision of supervisors in practice. Third, there is not only a lack of theoretically self-consistent discussion on the special problems of concurrent supervisors and employee supervisors' remuneration, but also a divorce of the institutional structure and application from good expectations. If the research background of the problem is placed in "tobacco regulatory science", it will be found that there is no inevitable connection between supervisors' compliance expectations and remuneration, but mainly depends on the provisions of legislation. Going back and forth between theory and practice of supervisors' remuneration, this paper combs and interprets the issue of supervisors' remuneration from the perspective of the legislative provisions and theoretical study under the Company Law, and analyzes the difference between the reality and the necessity of the Company Law with respect to the issue of supervisors' remuneration in the light of the legal principle of the Company Law, with the view to improvement of the rules of the Company Law.

Human African trypanosomiasis

2020 ◽  
pp. 1451-1459
Author(s):  
Reto Brun ◽  
Johannes Blum
Keyword(s):  
Trypanosoma Brucei ◽  
Human African Trypanosomiasis ◽  
Specific Treatment ◽  
Protozoan Parasite ◽  
Control Measures ◽  
Tsetse Flies ◽  
African Trypanosomiasis ◽  
Control Programmes ◽  
The 1960S ◽  
Stage 1

Human African trypanosomiasis (sleeping sickness) is caused by subspecies of the protozoan parasite Trypanosoma brucei. The disease is restricted to tropical Africa where it is transmitted by the bite of infected tsetse flies (Glossina spp.). Control programmes in the 1960s were very effective, but subsequent relaxation of control measures led to recurrence of epidemic proportions in the 1980s and 1990s. Control is now being regained. Untreated human African trypanosomiasis is almost invariably fatal. Specific treatment depends on the trypanosome subspecies and the stage of the disease. Drugs used for stage 1 include pentamidine and suramin, and for stage 2 include melarsoprol, eflornithine, and nifurtimox, but regimens are not standardized, and treatment is difficult and dangerous; all of the drugs used have many side effects, some potentially lethal.

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